When seeing the doctor, you feel better to know you will get some medicine. But the doctor knows that medicine is not always needed. Sometimes all a sick person needs is some reassurance (安想) that all will be well. In such cases the doctor may prescribe a placebo.

    A placebo is a sugar pill, a harmless shot, or an empty capsule. The patient thinks it is medicine and begins to get better. How does this happen?

    The study of the placebo opens up new knowledge about the way the human body can heal itself. It is as if there was a doctor in each of us. The doctor will heal the body for us if we let it. But it is not yet known just how the placebo works to heal the body. Some people say it works because the human mind fools itself. These people say that if the mind is fooled into thinking it got medicine, then it will act as if it did, and the body will feel better.

    Placebos don't always work. The success of this treatment seems to rest a lot with the relationship between the patient and the doctor. If the patient has lots of trust in the doctor and if the doctor really wants to help the patient, then the placebo is more likely to work. So in a way, the doctor is the most powerful placebo of all.

    A placebo can also have bad effects. If patients expect a bad reaction to medicine, then they'll also show a bad reaction to the placebo. Some doctors still think that if the placebo can have bad effects it should never be used. They think there is still not enough known about it.

    The strange power of the placebo does seem to suggest that the human mind is stronger than we think it is. There are people who say you can heal your body by using your mind. And the interesting thing is that even people who swear this is not possible have been healed by a placebo.

    What is it that makes people laugh? More than two thousand years ago the ancient Greek philosopher Aristotle defined (定义) jokes as the pleasure that results from a feeling of triumph(胜利) by showing we're better than someone else in a certain way. According to Aristotle and many other philosophers，all jokes depend mainly on showing inferiority in another person or group of persons—that is，putting it clearly，on showing that they are worse off than ourselves. Jokes raise our good opinion of ourselves at someone else's expense.

Showing how much better than other people we are is only one reason we like jokes. Someone may also use a joke to express their anger or their cruelty or any other kind of action that is not acceptable to us. We feel free to laugh when we hear about someone sliding on a banana skin. The joke lets us express those attitudes which are usually unacceptable to society. This is probably the reason why some of the jokes，especially those involving cruelty，are so popular with certain people.

    Besides，all jokes depend on our enjoyment of laughing at something that is strange and out of place because it's different from things which are happening around it. The same situation can be either sad or pleasant，depending entirely on how strange and out of place it is. If a girl in a bathing suit falls into a swimming pool，we don't laugh because nothing unusual has happened. But if a man in a smart suit falls in，the situation is at once unusual in a pleasant way and we laugh. A good joke-teller will always try to build up a situation in which one thing is expected until something unexpected suddenly happens，and so we laugh.

Sweet Dreams While You Sleep

    Did you sleep the day away on Friday March 21? Well, you should have done that because it was World Sleeping Day.

    This is the day of the year when people around the world care about their sleep and ask themselves questions about sleep.

    Why do we need sleep?

    Nobody as yet can give a perfect answer to this question. However, lab tests on rats have shown that lack (缺少) of sleep over about four weeks leads to a strong drop in body temperature, great weight loss and finally, death.

    How much sleep?

    Different people need different amounts of sleep. Eight hours a night is considered the average amount of sleep. For teenagers, the least number of sleeping hours advised by doctors are 10 hours for primary school students, nine for junior highs and eight for senior highs.

    Some people seem to get along just well with very little sleep at night. Leading American scientist Thomas Edison, for example thought of sleep to be a waste of time. He did, however take naps (打盹) during the day. On the other hand, Albert Einstein, another great scientist, said he needed at least ten hours sleep a night.

    How can we sleep well?

    Here are some of the most popular tips for a good night's sleep:

    Listen to your body clock, not your alarm clock (闹钟).

    Use your bed only to sleep.

    Get up and go to bed at the same time (also on weekends).

    Exercise in the morning and in the early afternoon. Don't exercise in the evening.

    Stop looking at that clock while you can't sleep! And don't worry.

    Avoid alcohol (酒精), caffeine (咖啡因) and smoking before going to bed.

    Keep the bedroom dark, quiet, and cool.

    The brain is a remarkable part. It's responsible for thoughts and feelings. Now a new study finds that going through tough times as a kid also can have an impact. The adult brains of people who lived through lots of stress before the age of six—and then became depressed or anxious as teenagers—were different compared with adults who had an easier childhood. It seems that teens changed the shape of their brains by internalizing (使内在化) the stresses experienced years earlier.

    Researchers already knew that the shape and size of a child's brain can change in response to lots of stress. They also knew that adults were more likely to be depressed if, as kids, they'd lived in poverty. Some studies showed that these depressed adults had unusual changes in their brain shape. But no one had tested if the early stress and later brain changes were linked.

    Scientists in England studied almost 500 boys from birth until the ages of 18 to 21. Sarah Jensen is one of the new study's authors. Almost all of the boys her team studied experienced some hard times as kids. And, she concludes, "This is not necessarily harmful." To some extent, that's just life. What can be dangerous, she says, is when children experience too many forms of difficulties. Her team's new data suggest that the tougher the childhood, the stronger the impact on the brain might be.

    What's happening in the world around us relates to how we feel. Her team linked more childhood stress to more depression. Still, she notes, it's possible that if you find support for anxiety or depression, you might be able to prevent the changes seen here. "If you can change the environment, you can change the course of things," Sarah says. So, she recommends, if teens develop anxiety or depression, it's good to ask for psychological doctors to give advice.

    A year back I received a full scholarship (奖学金) to attend the University of San Francisco. All of my hard work paid off. My mom had spent a lot on my attending a private high school, so I made sure to push myself: I volunteered, took part in various clubs, and graduated with honors. I was so excited to start a new part of my life.

    Soon enough, the big day came, but it wasn't like what I had thought. The first two weeks were the most difficult days of my entire life. Every night I would cry myself to sleep. I was missing my family, my home and everything in my hometown so much and I didn't know how to deal with my broken heart.

    To distract myself, I threw myself into my studies. I also found a ton of jobs. In any free time, I started forcing myself to go to the gym. I wanted to keep every part of my day busy so I wouldn't think about how lonely I felt. Soon after, I began to control my eating, considering it another solution to my homesickness(想家). But soon there was something wrong with me.

    Finally, I went to see a doctor. When the doctor told me I had no choice but to take time away from school, I started to fear. How could I stop? School was what I was best at. "I'm not so bad," I thought in my head. But the result was that I was taken to hospital again a month later and my mother came heartbrokenly. I had to take a semester off from school, and go to the treatment center near my home.

    If there are girls who are suffering similarly, I hope you know that there is hope and that you should have a positive attitude towards life. Though you may feel alone, there are so many people who can understand your struggle. That's why I want to share my story.

    An elderly carpenter was ready to retire. He told his employer of his plans to leave the house building business and enjoy his late life.

    The employer was sorry to see his good worker go and asked if he could build just one more house as a personal favor. The carpenter said yes, but in time it was easy to see that his heart was not in his work. He did his job carelessly and used inferior materials. It was an unfortunate way to end his career.

    When the carpenter finished his work, the employer came to examine the house and handed the front-door key to the carpenter. "This is your house," he said, "my gift to you."

    What a shock! What a shame! If he had only known he was building his own house, he would have done it all so differently. Now he had to live in the home he had built none too well.

    So it is with us. We build our lives in a distracted way, reacting rather than acting, willing to put up less than the best. At important points we do not give the job our best effort. Then with a shock we look at the situation we have created and find that we are now living in the house we have built. If we had realized, we would have done it differently.

    Think of yourself as the carpenter. Think about your house. Each day you hammer a nail, place a board, or build a wall. Build wisely. It is the only life you will ever build. Even if you live it for only one day more, that day deserves to be lived well. The plaque (匾牌) on the wall says, "Life is a do-it-yourself project."

    Who could say it more clearly? Your life today is the result of your attitudes and choices in the past. Your life tomorrow will be the result of your attitudes and the choices you make today.